1. Field of the Invention
The present invention relates to an antirotation linkage that allows freedom of movement in two coordinate directions of a rocket motor nozzle with respect to the primary or longitudinal axis of a rocket motor in which it is rotatably mounted for angular displacement of the thrust vector for steering control, but which restricts rotation of the nozzle about such primary axis.
2. Description of the Prior Art
Thrust vector control systems for rocket propelled vehicles are known in the prior art in which the nozzle, including the nozzle throat and expansion cone, are rotatably mounted or pivoted, being carried by a spherical or other bearing, for omni axial rotation of the nozzle relative to the rocket vehicle so that the thrust vector can be angularly displaced to steer the vehicle.
Systems of this type including hydraulic cylinders that are positioned externally of the nozzle for deflecting or "slewing" the nozzle to change the direction of flight of the vehicle are disclosed in U.S. Pat. No. 3,049,877 granted to A. Sherman on Aug. 2, 1962 and U.S. Pat. No. 3,230,708 granted to D. H. Huang et al on Jan. 25, 1966. Thrust vector control systems in which the nozzle is carried by the ball or race of a spherical bearing, and which include a "self actuation" or an internal actuation system for deflecting the nozzle to steer the vehicle, are disclosed in U.S. Pat. No. 3,912,172 granted Oct. 14, 1975 to Thomas E. Bolner, and in the pending application for U.S. patent of Thomas E. Bolner bearing Ser. No. 260,941, filed May 6, 1981, now Pat. No. 4,435,023, issued Mar. 6, 1984, the disclosures of which Bolner patent and pending patent application, by reference, are incorporated herein.
A problem in rocket technology is a tendency of the nozzle to rotate about the primary or longitudinal axis of the rocket vehicle in which it is mounted for rotation. This places undesirable, torsional, shear stresses on the nozzle bearings, and reduces the ability to steer the rocket vehicle accurately.